Creating IF statement

I need a SQL statement to do this:

Parse first 7 digits of YTD_2011_QB.Account field of source to get the account number. If the account number falls in the range (6727000, 6745000, 6748000, 6768100, 6787000, 6790000, 6863000, 6864000) then populate ZLGLACCT with the concatenation of first 7 digits of YTD_2011_QB.csv.account and last 10 characters of YTD_2011_QB.csv.class field. Else, Populate ZLGLACCT with first 7 digit of YTD_2011_QB.account